Potassium carbonate manufacturer and service provider

Potassium carbonate, commonly known as potash, is an important inorganic salt compound with the chemical formula K ₂ CO ∝ and a molecular weight of 138.21. It is also referred to as grass alkali or pearl ash when its purity is low. The following provides a detailed explanation from three aspects: physical properties, chemical properties, and reaction characteristics:

1、 Physical properties

Appearance and Form

At room temperature, potassium carbonate appears as white crystalline powder or granules, with a fine texture and no special odor. Its appearance is similar to that of soda ash (sodium carbonate), but can be distinguished by its chemical properties.

Solubility

Water solubility: Potassium carbonate is easily soluble in water, with a solubility of up to 111g/100mL at 25 ℃, forming a colorless and transparent solution.

Alcohol insolubility: Insoluble in organic solvents such as ethanol and ether, this characteristic can be used for separation and purification.

Deliquescence: It has strong hygroscopicity and is prone to moisture absorption and deliquescence when exposed to air. It needs to be sealed and stored.

Density and melting point

The density is about 2.428g/cm ³ (25 ℃), slightly higher than that of pure alkali (2.54g/cm ³).

The melting point is 891 ℃, stable at high temperatures, but decomposition occurs beyond the melting point.

2、 Chemical properties

Thermal stability

Potassium carbonate decomposes into potassium oxide (K ₂ O) and carbon dioxide (CO ₂) at high temperatures (>891 ℃), and the reaction equation is:

K₂CO₃ → K₂O + CO₂↑

When heated together with carbon (C), it can be reduced to metallic potassium (K), while generating carbon monoxide (CO), and the reaction is:

K₂CO₃ + 2C → 2K + 3CO↑

Reaction with acid

Reacting with acids (such as hydrochloric acid HCl, sulfuric acid H ₂ SO ₄) to generate corresponding potassium salts, water, and carbon dioxide, for example:

K₂CO₃ + 2HCl → 2KCl + H₂O + CO₂↑

The reaction is intense and releases a large amount of bubbles, which can be used for laboratory preparation of carbon dioxide.

Reaction with alkali and salt

Double decomposition reaction: reacts with some alkali (such as calcium hydroxide Ca (OH) ₂) or salt (such as calcium chloride CaCl ₂) to form a precipitate, for example:

K₂CO₃ + Ca(OH)₂ → CaCO₃↓ + 2KOH

K₂CO₃ + CaCl₂ → CaCO₃↓ + 2KCl

Precipitation characteristics: The generated calcium carbonate (CaCO ∝) is a white precipitate that can be used to test carbonate ions (CO ∝ ②⁻).

3、 Reaction characteristics

Reaction with carbon and nitrogen/ammonia

At high temperatures, potassium carbonate reacts with carbon and nitrogen (N ₂) or ammonia (NH ∝) to produce potassium cyanide (KCN), which reacts as follows:

K₂CO₃ + 3C + N₂ → 2KCN + 3CO↑

K₂CO₃ + 3C + 2NH₃ → 2KCN + 3H₂↑ + 3CO↑

Potassium cyanide is a highly toxic compound that requires strict control.

Reaction with halogens

Reacts with halogens (such as chlorine gas Cl ₂, bromine Br ₂) to produce potassium halides (such as KCl, KBr) and carbon dioxide, for example:

K₂CO₃ + Cl₂ → 2KCl + CO₂↑

Reaction with sulfur, tellurium, and potassium nitrate

Heat with sulfur (S), tellurium (Te), and potassium nitrate (KNO3) to generate potassium thiosulfate (K ₂ S ₂ O3) or potassium tellurite (K ₂ TeO3), for example:

K₂CO₃ + S + KNO₃ → K₂S₂O₃ + CO₂↑ + N₂↑

4、 Application relevance

Industrial preparation

The chemical properties of potassium carbonate determine its preparation process. For example, the ion exchange method generates potassium bicarbonate through resin transformation, which is then calcined and decomposed into potassium carbonate; The electrolysis method involves the reaction of potassium hydroxide with carbon dioxide to produce potassium bicarbonate, which is then purified by calcination.

Application Fields

Glass manufacturing: As a flux, it utilizes its high-temperature decomposition characteristics to reduce the melting temperature of glass.

Dye industry: As an intermediate in the production of vat dyes, it adjusts the pH value by utilizing its reaction characteristics with acids.

Dry powder fire extinguishing agent: mixed with soda ash, releases carbon dioxide through reaction with acid to extinguish the fire.

Other fields, such as electroplating (buffering agents), leather making (degreasing agents), etc., are closely related to their chemical properties.

5、 Safety and Storage

Safety precautions

Potassium carbonate is irritating to the skin and eyes, and protective equipment should be worn during operation.

Reacting violently with acid, avoid contact with strong acids to prevent suffocation caused by excessive carbon dioxide.

Storage conditions

It should be sealed and stored in a dry, cool place to avoid moisture absorption and clumping.

Stay away from acidic substances to prevent reactions.